1. Field of the Invention
The present invention relates to a self-closing water-saving valve assembly, especially to a self-closing water-saving valve assembly that can reduce the water hammer and has prolonged lifespan.
2. Description of the Prior Arts
A conventional valve assembly is mounted on a top of a tap and has the advantage of a simple structure. However, a user has to raise his hand to switch off the valve assembly on the top of the tap after washing, and this movement causes waste of water.
To solve the shortcoming mentioned above, an infrared-sensor valve assembly is provided. When being washed, hands of a user are placed at a sensing zone to activate the infrared-sensor valve assembly by infrared light. After washing, the infrared-sensor valve assembly is automatically switched off because the hands are removed. Therefore, a water-saving effect is achieved. However, as the sensing zone is a specific area, users may have to try many times to properly place the hands in the sensing zone, which is inconvenient.
As a result, a self-closing water-saving valve assembly is invented. With reference to FIG. 10, the self-closing water-saving valve assembly has a casing 91, a pushing rod 92, a timing gasket 93 and a closing gasket 94. The casing 91 has an inlet 911, an outfall 912 and a timing channel 913. The pushing rod 92 is mounted in the timing channel 913 and the inlet 911. A bottom end of the pushing rod 92 protrudes out of the casing 91. The timing gasket 93 is mounted around the pushing rod 92 and abuts an inner wall of the timing channel 913. The closing gasket 94 is mounted on a top end of the pushing rod 92 and selectively seals the inlet 911.
With reference to FIG. 11, when the self-closing water-saving valve assembly is in use, the pushing rod 92 is pushed up such that the closing gasket 94 departs from the inlet 911. Then the water in the water pipe can enter the inlet 911 and flow out from the outfall 912. When the water is passing through, the water keeps hitting against the top end of the pushing rod 92 and accordingly the pushing rod 92 moves downward gradually. However, because the timing gasket 93 mounted securely to the pushing rod 92 abuts the inside wall of the timing channel 913 and generates an abrasion force, the pushing rod 92 moves down slowly. With reference to FIG. 10, finally, the closing gasket 94 on the top end of the pushing rod 92 seals the inlet 911 again and the water stops flowing out, which achieves the self-closing effect.
Nevertheless, the conventional self-closing water-saving valve assembly still has two shortcomings
First, the moment the closing gasket 94 seals the inlet 911, the water flowing in the water pipe hits the sealed inlet 911 suddenly and stops flowing such that a series of positive and negative pressure waves are generated and vibrate in the water pipe until the energy is exhausted by friction. This condition is so-called water hammer and causes discordant noises and damage to the water pipe. Besides, because the water pressure is large, a force applied to the pushing rod 92 to open the valve assembly is also large to resist the water pressure. The operation is not smooth and inconvenient.
Second, every time the valve assembly is opened and closed, the timing gasket 93 rubs against the inside wall of the timing channel 913. So after a period of time of use, the timing gasket 93 may be worn away and an outer diameter of the timing gasket 93 decreases. The abrasion force between the timing gasket 93 and the timing channel 913 is weakened, which speeds up the downward movement of the pushing rod 92 and reduces the amount of the water flowing out. As a result, a lifespan of the conventional self-closing water-saving valve assembly is shortened.
To overcome the shortcomings, the present invention provides a self-closing water-saving valve assembly to mitigate or obviate the aforementioned problems.